APIS to build peer to peer messaging applications

ABSTRACT

The claimed method and system is an API set to support a multicast programming model for implementation on top of a service oriented framework, specifically a service oriented messaging system.

BACKGROUND

Group communication technologies on the Internet allow users with commoninterest to collaborate, share files, chat with one another, multi-castaudio and video for presentations and group meetings, and engage inmulti-player gaming. Indeed, the ability for group formation in an adhoc basis present significant advantages to allow users with commoninterests to gather in a virtual area or group that may be segregatedfrom the general Internet population thereby facilitating usefuldiscussion in collaboration between such like minded individuals.Currently, however, most group communication and formation takes placein a server centric environment whereby all communication flows to orthrough large central servers to which individuals may connect to joinand participate in the group.

Peer-to-peer technologies enable users to contact one another in aserverless environment, free from the constraints of server basedInternet communication. In a peer-to-peer based system, a usersanonymity and privacy may be maintained since communication occursdirectly between peers within the network. However, while individualcommunication and file sharing is relatively well established inpeer-to-peer networks, establishing, discovering, joining, maintaining,and sharing information in a group peer-to-peer environment is not wellestablished. However, individuals have grown accustomed to the benefitsprovided by such grouping technology in the server centric environment.

SUMMARY

The claimed method and system is an API set to support a multicastprogramming model for implementation on top of a service orientedframework, specifically a service oriented messaging system. It providesapplication-layer multicast capability without requiring an IP multicastinfrastructure. The claimed system enables service oriented applicationsto implement multicasting communications easily and efficiently.Moreover, the claimed multicast method and system of the claims providesmanagement processes for creating and maintaining mesh topologies forpeer-to-peer applications that may enhance multicast processes. Some ofthese processes may include: a channel monitoring and delivery service;a flooding and filtering service; an advertising service; a connectionmaintenance service; a cross domain Internet wide mesh capability; and aserverless peer resolution service.

DRAWINGS

FIG. 1 is a block diagram of a computing system that may operate inaccordance with the claims;

FIG. 2 illustrates a Open Systems Interconnection Model;

FIG. 3 illustrates a possible service oriented messaging system in whichthe claimed system may be built upon;

FIG. 4 illustrates message communications using the messaging system ofFIG. 3;

FIG. 5 illustrates a multicasting mesh topology;

FIG. 6 illustrates a logical mesh embodiment of the claimed system;

FIG. 7 illustrates a general object model for use in implementing themesh in an embodiment of the claims;

FIG. 8 illustrates a general flowchart for creating a mesh in anembodiment of the claims;

FIG. 9 illustrates a neighbor connection process in an embodiment of theclaims;

FIG. 10 may illustrate a synchronizer process in an embodiment of theclaims;

FIG. 11 may illustrate the exchange of various synchronization relatedmessages between a pair of neighbors, where the initiator is the newnode;

FIG. 12 may illustrate the synchronization process between a pair ofexisting nodes in the mesh;

FIG. 13 may illustrate the synchronization process between an existingnode and a new node, where the existing node is the initiator;

FIG. 14 may illustrate a general flooding process in an embodiment ofthe claims;

FIG. 15 illustrates a message handling process in an embodiment of theclaims;

FIG. 16 illustrates a mesh management process in an embodiment of theclaims; and

FIG. 17 is flowchart of a method in accordance with the claims.

DESCRIPTION

Although the following text sets forth a detailed description ofnumerous different embodiments, it should be understood that the legalscope of the description is defined by the words of the claims set forthat the end of this patent. The detailed description is to be construedas exemplary only and does not describe every possible embodiment sincedescribing every possible embodiment would be impractical, if notimpossible. Numerous alternative embodiments could be implemented, usingeither current technology or technology developed after the filing dateof this patent, which would still fall within the scope of the claims.

It should also be understood that, unless a term is expressly defined inthis patent using the sentence “As used herein, the term ‘______’ ishereby defined to mean . . . ” or a similar sentence, there is no intentto limit the meaning of that term, either expressly or by implication,beyond its plain or ordinary meaning, and such term should not beinterpreted to be limited in scope based on any statement made in anysection of this patent (other than the language of the claims). To theextent that any term recited in the claims at the end of this patent isreferred to in this patent in a manner consistent with a single meaning,that is done for sake of clarity only so as to not confuse the reader,and it is not intended that such claim term be limited, by implicationor otherwise, to that single meaning. Finally, unless a claim element isdefined by reciting the word “means” and a function without the recitalof any structure, it is not intended that the scope of any claim elementbe interpreted based on the application of 35 U.S.C. § 112, sixthparagraph.

FIG. 1 illustrates an example of a suitable computing system environment100 on which a system for the blocks of the claimed method and apparatusmay be implemented. The computing system environment 100 is only oneexample of a suitable computing environment and is not intended tosuggest any limitation as to the scope of use or functionality of themethod and apparatus of the claims. Neither should the computingenvironment 100 be interpreted as having any dependency or requirementrelating to any one component or combination of components illustratedin the exemplary operating environment 100.

The blocks of the claimed method and apparatus are operational withnumerous other general purpose or special purpose computing systemenvironments or configurations. Examples of well known computingsystems, environments, and/or configurations that may be suitable foruse with the methods or apparatus of the claims include, but are notlimited to, personal computers, server computers, hand-held or laptopdevices, multiprocessor systems, microprocessor-based systems, set topboxes, programmable consumer electronics, network PCs, minicomputers,mainframe computers, distributed computing environments that include anyof the above systems or devices, and the like.

The blocks of the claimed method and apparatus may be described in thegeneral context of computer-executable instructions, such as programmodules, being executed by a computer. Generally, program modulesinclude routines, programs, objects, components, data structures, etc.that perform particular tasks or implement particular abstract datatypes. The methods and apparatus may also be practiced in distributedcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed computing environment, program modules may be located inboth local and remote computer storage media including memory storagedevices.

With reference to FIG. 1, an exemplary system for implementing theblocks of the claimed method and apparatus includes a general purposecomputing device in the form of a computer 110. Components of computer110 may include, but are not limited to, a processing unit 120, a systemmemory 130, and a system bus 121 that couples various system componentsincluding the system memory to the processing unit 120. The system bus121 may be any of several types of bus structures including a memory busor memory controller, a peripheral bus, and a local bus using any of avariety of bus architectures. By way of example, and not limitation,such architectures include Industry Standard Architecture (ISA) bus,Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, VideoElectronics Standards Association (VESA) local bus, and PeripheralComponent Interconnect (PCI) bus also known as Mezzanine bus.

Computer 110 typically includes a variety of computer readable media.Computer readable media can be any available media that can be accessedby computer 110 and includes both volatile and nonvolatile media,removable and non-removable media. By way of example, and notlimitation, computer readable media may comprise computer storage mediaand communication media. Computer storage media includes both volatileand nonvolatile, removable and non-removable media implemented in anymethod or technology for storage of information such as computerreadable instructions, data structures, program modules or other data.Computer storage media includes, but is not limited to, RAM, ROM,EEPROM, flash memory or other memory technology, CD-ROM, digitalversatile disks (DVD) or other optical disk storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or any other medium which can be used to store the desired informationand which can accessed by computer 110. Communication media typicallyembodies computer readable instructions, data structures, programmodules or other data in a modulated data signal such as a carrier waveor other transport mechanism and includes any information deliverymedia. The term “modulated data signal” means a signal that has one ormore of its characteristics set or changed in such a manner as to encodeinformation in the signal. By way of example, and not limitation,communication media includes wired media such as a wired network ordirect-wired connection, and wireless media such as acoustic, RF,infrared and other wireless media. Combinations of the any of the aboveshould also be included within the scope of computer readable media.

The system memory 130 includes computer storage media in the form ofvolatile and/or nonvolatile memory such as read only memory (ROM) 131and random access memory (RAM) 132. A basic input/output system 133(BIOS), containing the basic routines that help to transfer informationbetween elements within computer 110, such as during start-up, istypically stored in ROM 131. RAM 132 typically contains data and/orprogram modules that are immediately accessible to and/or presentlybeing operated on by processing unit 120. By way of example, and notlimitation, FIG. 1 illustrates operating system 134, applicationprograms 135, other program modules 136, and program data 137.

The computer 110 may also include other removable/non-removable,volatile/nonvolatile computer storage media. By way of example only,FIG. 1 illustrates a hard disk drive 140 that reads from or writes tonon-removable, nonvolatile magnetic media, a magnetic disk drive 151that reads from or writes to a removable, nonvolatile magnetic disk 152,and an optical disk drive 155 that reads from or writes to a removable,nonvolatile optical disk 156 such as a CD ROM or other optical media.Other removable/non-removable, volatile/nonvolatile computer storagemedia that can be used in the exemplary operating environment include,but are not limited to, magnetic tape cassettes, flash memory cards,digital versatile disks, digital video tape, solid state RAM, solidstate ROM, and the like. The hard disk drive 141 is typically connectedto the system bus 121 through a non-removable memory interface such asinterface 140, and magnetic disk drive 151 and optical disk drive 155are typically connected to the system bus 121 by a removable memoryinterface, such as interface 150.

The drives and their associated computer storage media discussed aboveand illustrated in FIG. 1, provide storage of computer readableinstructions, data structures, program modules and other data for thecomputer 110. In FIG. 1, for example, hard disk drive 141 is illustratedas storing operating system 144, application programs 145, other programmodules 146, and program data 147. Note that these components can eitherbe the same as or different from operating system 134, applicationprograms 135, other program modules 136, and program data 137. Operatingsystem 144, application programs 145, other program modules 146, andprogram data 147 are given different numbers here to illustrate that, ata minimum, they are different copies. A user may enter commands andinformation into the computer 20 through input devices such as akeyboard 162 and pointing device 161, commonly referred to as a mouse,trackball or touch pad. Other input devices (not shown) may include amicrophone, joystick, game pad, satellite dish, scanner, or the like.These and other input devices are often connected to the processing unit120 through a user input interface 160 that is coupled to the systembus, but may be connected by other interface and bus structures, such asa parallel port, game port or a universal serial bus (USB). A monitor191 or other type of display device is also connected to the system bus121 via an interface, such as a video interface 190. In addition to themonitor, computers may also include other peripheral output devices suchas speakers 197 and printer 196, which may be connected through anoutput peripheral interface 190.

The computer 110 may operate in a networked environment using logicalconnections to one or more remote computers, such as a remote computer180. The remote computer 180 may be a personal computer, a server, arouter, a network PC, a peer device or other common network node, andtypically includes many or all of the elements described above relativeto the computer 110, although only a memory storage device 181 has beenillustrated in FIG. 1. The logical connections depicted in FIG. 1include a local area network (LAN) 171 and a wide area network (WAN)173, but may also include other networks. Such networking environmentsare commonplace in offices, enterprise-wide computer networks, intranetsand the Internet.

When used in a LAN networking environment, the computer 110 is connectedto the LAN 171 through a network interface or adapter 170. When used ina WAN networking environment, the computer 110 typically includes amodem 172 or other means for establishing communications over the WAN173, such as the Internet. The modem 172, which may be internal orexternal, may be connected to the system bus 121 via the user inputinterface 160, or other appropriate mechanism. In a networkedenvironment, program modules depicted relative to the computer 110, orportions thereof, may be stored in the remote memory storage device. Byway of example, and not limitation, FIG. 1 illustrates remoteapplication programs 185 as residing on memory device 181. It will beappreciated that the network connections shown are exemplary and othermeans of establishing a communications link between the computers may beused.

FIG. 2 illustrates an Open Systems Interconnection (“OSI”) Modeldeveloped by the International Organization for Standardization (“ISO”),which may be used to describe an aspect of the method and system of theclaims. OSI is a standard description for how messages may betransmitted between any two points in a telecommunication network.

According to the OSI model, the process of communication between two endpoints in a telecommunication network may be divided into layers, witheach layer adding its own set of special, related functions. Acommunicating computer may be equipped with these seven layers offunction. In communicating a given message between users, there may be aflow of data through each layer at one end down through the layers inthat computer and, at the other end, when the message arrives, anotherflow of data up through the layers in the receiving computer andultimately to the end user or program. The actual programming andhardware that furnishes these seven layers of function is usually acombination of the computer operating system, applications, TransmissionControl Protocol (“TCP”)/Internet Protocol (“IP”) or alternativetransport and network protocols, and the software and hardware thatenables a signal to be placed on one of the lines attached to thecomputer.

OSI divides communication into seven layers. The layers are in twogroups. The upper layers 209 are used whenever a message passes from orto a user and the lower layers 208 are used when any message passesthrough the host computer. Messages intended for this computer pass tothe upper layers 209. Messages destined for some other host are notpassed up to the upper layers but are forwarded to another host. Theseven layers are briefly described as follows.

The physical layer 201 defines the physical characteristics of theinterface, such as mechanical components and connectors, electricalaspects such as voltage levels representing binary values, andfunctional aspects such as setting up, maintaining, and taking down thephysical link. Well-known physical layer interfaces for datacommunication include serial interfaces, parallel interfaces, and thephysical specifications for LAN systems such as Ethernet and token ring.

The data link layer 202 defines the rules for sending and receivinginformation across a physical connection between two systems. Data linksare typically network segments (not inter-networks) and point-to-pointlinks. Data is packaged into frames for transport across the underlyingphysical network. Some reliability functions may be used, such asacknowledgment of received data.

The Network Layer 203 provides inter-networking services that deliverdata across multiple networks. An internetwork addressing scheme assignseach network and each node a unique address. The network layer supportsmultiple data link connections. In the Internet Protocol suite, IP isthe network layer internetworking protocol.

The Transport Layer 204 provides end-to-end communication services andensures that data is reliably delivered between those end systems. Bothend systems establish a connection and engage in a dialog to track thedelivery of packets across a network. The protocol also regulates theflow of packets to accommodate slow receivers and ensures that thetransmission is not completely halted if a disruption in the linkoccurs. Transmission Control Protocol, (“TCP”) may be a transport layerprotocol.

The Session Layer 205 coordinates the exchange of information betweensystems by using conversational techniques, or dialogs. Dialogs are notalways required, but some applications may require a way of knowingwhere to restart the transmission of data if a connection is temporarilylost, or may require a periodic dialog to indicate the end of one dataset and the start of a new one.

The Presentation Layer 206 contains protocols that are part of theoperating system and application the user runs on a workstation.Information is formatted for display or printing in this layer. Codeswithin the data are interpreted, and data encryption and translation arealso handled in this layer.

The Application Layer 207 provides defined procedures for accessing theunderlying network services. The application layer is used to define arange of user applications.

While multicasting technologies are being developed for the lower levels208 of the OSI model, i.e., the transport/networking layers, the claimedsystem focuses in on providing an application-level programming modelfor implementing multicasting at the upper levels 209 of the OSI model.Thus, using the method and system of the claims, a developer mayimplement multicasting functionality without requiring an IP multicastinfrastructure. Moreover, the claimed system may improve a servicesoriented programming model, which is described below.

Service Oriented Frameworks and Programming Models

Service-orientation may differ from object-orientation primarily in howservice oriented frameworks define “application.” Object-orienteddevelopment may focus on applications that are built from interdependentclass libraries, whereas service-oriented development may focus onsystems that are built from a set of autonomous services. A service maysimply be a program that one interacts with via message exchanges.However, unlike existing distributed object technologies, services mayinteract with their clients only through a well-defined XML interface.Behaviors such as passing complete classes, methods and calls, acrossservice boundaries may not be allowed. Thus, application developers andsystem integrators may not require specific knowledge of the underlyingobject models, type systems and protocols of the software beingintegrated.

Instead of integrating disparate applications via direct objectactivations as in distributed object systems, applications may expose aset of “services” that other applications can utilize. Applicationsutilizing the services framework may expose their services usingstandards-based protocols and policy definitions that can be dynamicallyacquired. This uncoupling of the applications that make up connectedsystems may enable simpler integration, more flexibility in adaptingsystems to changes over time, and also may enable more reliableoperations.

Existing service oriented programming models may implement an existingupper-OSI level messaging service, such as Simple Object Access Protocol(“SOAP”). SOAP may operate as an upper level OSI service that provides aschema for messages. One possible embodiment of a messaging system thatutilizes the SOAP protocol is illustrated in FIG. 3. The illustratedmessaging architecture, (hereinafter, “Message Bus”) may be viewed as anapplication programming interface (“API”) for simplifying thedevelopment and maintenance of a SOAP node. The claimed system andmethod may be implemented on any service oriented model providing basicupper-level message handling, but for the purposes of demonstration, theclaimed method and system will be described using the Message Busillustrated in FIG. 3.

As illustrated in FIG. 3, the Message Bus networking layer 301 andtransport 302 may consist of any of the typical transportlayer/networking layer protocols in existence. TCP/IP is a populartransport layer/networking layer protocol and may not need to be IPmulticast enabled, which is an advantage of using the application-levelmulticast system of the claims. The transport layer may encapsulate anetworking mechanism such as an IP socket, or named pipe, or anymechanism by which data may be communicated. Message Bus transports 303may translate messages into actual bytes to be communicated on the wirevia the data-link and physical layers.

Moving up to the Presentation/Session Layer 304, a port object 305 mayrepresent a configurable, logical conduit for messages. Each port object305 has a collection of transports 303 that the port uses to translatelogical messages into actual network communication. Ports are internallyimplemented as a pair of pipeline objects: a send pipeline 306 and areceive pipeline 307. Each pipeline may support pluggable messagehandlers (not shown), constituting port extensions, which can inspectand manipulate messages traveling along the pipeline. A typical node inan application using the Message Bus may instantiate only a single Portobject, although it is possible to create more than one. The remainderof this description will refer to ports in effort to assist the userconceptualize the description, but the use of ports may not be necessaryin a modem message bus architecture.

At the application layer 309, application code 310 may send messages toa port object via a channel object 308. Channel objects come in avariety of embodiments, which may be narrowed down to two sets: sendchannels and receive channels. A single channel class may also implementboth a send and a receive channel.

The Message Bus may support a variety of channel implementations toallow for a variety of message exchange patterns. For example, a simplechannel for one-way datagram-style messages may just represent anultimate receiver. On the other hand, a more complex channel may supportcorrelated two way messaging, reliable messaging or message durabilityacross executions of the application. The channel is the first point atwhich a Message object created by application code may be handed toinfrastructure code (e.g., IP), and from the perspective of theapplication code, the channel is the first point of extensibility in theMessage Bus architecture.

The general process of sending and receiving a message using the MessageBus Framework may be as follows.

-   -   1. A Message object is created by the initial sender.    -   2. A message is sent by passing a reference to the Message        object to a channel.    -   3. The channel passes the message to the port object with which        the channel is associated.    -   4. The port injects the message into the port's send pipeline        where the message is processed serially by each message handler        registered with the pipeline.    -   5. When the message reaches the end of the send pipeline, the        port passes the message reference to a transport object        registered with the port. The transport object is selected based        on the address of the next hop for the message.    -   6. The transport layer formats the message into a stream of        bytes and pushes the bytes onto the network.

At this point the message has left the SOAP node and has entered anetwork cloud. Until the message reaches the next SOAP node in itsjourney, the message is no longer subject to the Message Bus or SOAP.Instead, the message may be a stream of bytes passing through anetworking protocol such as TCP/IP or HTTP.

At some point the bytes of the message reach a listening node on thenetwork that is a SOAP node. The following may take place at thelistening node.

-   -   1. A transport-derived object receives a stream of bytes from        which it creates a Message object in memory. Message headers are        read entirely into memory, however, the message content remains        in the transport and possibly on the wire until it is needed.    -   2. The transport then passes the Message reference into the        receive pipeline of the Port with which the Transport object is        registered.    -   3. The message is processed serially by each message handler        registered with the receive pipeline. If a message handler        chooses to, it can pull the message from receive pipeline, and        pass it to a channel associated with the message handler.    -   4. If the message makes it to the end of the receive pipeline on        the port, the port passes the message to an application-defined        message handler registered with the port's main receive channel.    -   5. Application code has a reference to the Message object, with        which it may do what it pleases. Typically the action-header of        the message is checked, and the content of the message is        processed.    -   6. Once the application code is finished with the message, the        Message Bus reads and throws away any unread bytes left in the        message content to clear out the transport and the Message        object is left for garbage collection.    -   7. If the message passed through a SOAP intermediary on its way        from the initial sender to the ultimate receiver, then the        intermediary also processes the message using the receiving        steps as well as the sending steps as previously outlined. An        intermediary is a node that is both a sender and a receiver of a        single message. A SOAP router is a common example of an        intermediary.

FIG. 4 illustrates the path that a message may take from initial sender401 to ultimate receiver 402 through two intermediaries 403, 404. Thefigure illustrates that only the send pipeline 405 may be utilized bythe initial sender 401, and only the receive pipeline 406 is used by theultimate receiver. Meanwhile, with the intermediaries 403, 404, both thesend 407, 408 and receive pipelines 409, 410 are utilized in processingthe message. Note that the roles of initial sender and ultimate receiverwould be swapped in the journey of a response message.

While the Message Bus framework provides a basic mechanism forimplementing services using a service oriented framework, there is noprovision for enabling multicast functionality. The claimed method andsystem builds upon such a service oriented Message Bus architecture toprovide developers the capability of building on top of the serviceoriented model to add multicasting functionality to their applications.

Multicast Mesh Systems

The claimed system and method may implement a particular multicasttopology known as a mesh. FIG. 5 illustrates a possible mesh topology.Generally, a member of a multicast group may be referred to as a node501 and the group may be considered a mesh 500 and is represented by aset of nodes 501-508 that are interconnected to each other usingcommunication channels, e.g., 509. Each node 501-508 in the mesh may beable to communicate a message to each and every other node in the meshthrough a propagation process, in which each message sent by one node,e.g., node 501, is passed on to neighboring nodes 502-505, whichcontinue passing them on to their neighbor nodes until each nodereceives the message. When a node has multiple connections, it mayreceive a message and make copies of the message for sending along eachchannel connected to it. Because the direction of propagation generallyflows away from the message sender and resembles physical flooding, thepropagation of messages using multicasting is generally called flooding.Each node in a multicast mesh may receive and be knowledgeable of anymessages flooded on the network, i.e., what one node knows via a floodedmessage, every node in the mesh knows. Accordingly, it may be beneficialto have a mesh of a reasonable size or rules regarding when messagesshould continue-to be flooded.

Multicast Mesh Embodiment Using a Service Oriented Messaging System

FIG. 6, illustrate a general embodiment of the claimed multicast meshsystem. In this embodiment, a peer node 601 is a node connected to amesh 602. A mesh may be a named set of peer nodes 601-605 that aremultiply connected by neighbor channels 607-611 to form a couplednetwork of nodes for the purposes of propagating data in the form ofmessages or point-to-point data streams. The mesh is built based onconnections to neighbor nodes, where a neighbor node in a mesh is a peernode that is one communication link away (is directly connected via acommunication channel).

A peer node may be associated with an instance of an application 612coupled to a mesh 602. A peer channel 613, 614 may be considered aspecific channel to a peer node for communication between an application612, or service (in service oriented language), and a mesh 602 via apeer node 601 of the mesh. An application may create a node but a nodecannot create an application. The application may create multiple nodesand each node may host multiple services. For example, consider a Chatapplication. The Chat application may create a node in a mesh calledChatMesh. It may create two different services, VideoService andTextService. Any text messages sent may be delivered to TextService andany video messages sent may be delivered to VideoService.

When initially connecting to a mesh, a peer node 601 may connect toanother peer node, e.g., 603, that is already connected to the mesh. Theconnecting peer node 601 may determine the address of the neighbor node603 connected to the mesh and send the neighbor node a solicitation tojoin the mesh. After connecting to the mesh, the new peer node 601 maycreate connections 608, 610 to additional neighbors, e.g., 604, 605within the mesh.

The purpose of a mesh may be to create a logical topology for theflooding of messages to all mesh nodes. To automatically achieve theoptimal topology for flooding, the mesh may maintain a signature, a setof contact nodes, and evaluates duplicate flooded messages to determinewhich neighbors are more efficient. Over time, connections may becreated and removed so that the mesh converges to a topology that isoptimal for flooding.

When a node disconnects from a mesh, it may potentially create a breakin the mesh known as a mesh partition. Peer nodes use a mesh signature(to be described below) and mesh contact information to detect andrepair a graph partition.

The peer channels 613, 614 may be communication channels that send andreceive between the application 612 and a peer node 601. They may appearto the application as multicast channels, without requiring an IPenabled multicasting infrastructure. Each peer channel 613, 614 may beassociated with a peer node 601. The peer node 601 may be responsiblefor implementing the mesh algorithms (e.g., optimization, partitiondetection and repair) and flooding messages throughout the mesh. Eachpeer node may provide its own service, called a node service, whichinteracts with a set of neighboring node services using reliable MessageBus channels. This node service may be implemented on top of the serviceframework and uses reliable channels over TCP and HTTP transport, forexample.

Messages sent on a peer channel may be destined to a particular serviceoffered by another node in the mesh. Every node in the mesh may receivea copy of each message sent on the mesh. When a node receives a message,it may deliver it to any associated peer channels which implement themessage's intended service. In order to propagate the message to eachnode in the mesh, the originating node may send the message to each ofits neighbors. Those neighbors may pass it on to their neighbors, and soforth. The actual flooding algorithm is described below.

An application message may be tunneled from one neighbor peer node 601to another 602, for example, by encapsulating the application message,or inner message, in another outer message addressed to the node'sneighbor. A new outer message may be created per neighbor. In this way,the original message, including its destination service address, mayremain unchanged from node to node. All nodes may be reachable from allother nodes. To the extent to which this is not true (e.g., nodes beingbehind untraversable firewalls), the resilience of the mesh degrades.

Object Model Embodiment

FIG. 7 illustrates the objects that may implement an embodiment of theclaimed system. The objects of the claimed multicast system may consistof a PeerChannel Factory 701, a PeerChannel 702, a PeerListenerFactory703, a PeerListener 704, a PeerNode 705, a Synchronizer 706, aMaintainer 707, a Connector 708, a Flooder 709, a NeighborManager 710,and a Neighbor 711. Logically, the logical peer node described above maybe implemented as the set of objects consisting of the PeerNode 705,Synchronizer 706, a Connector 708, a Maintainer 707, a Flooder 709, anda NeighborManager 710.

PeerChannelFactory 701 may be responsible for spawning PeerChannels 702.The PeerChannelFactory 701 may also maintain a collection of activechannels that it creates. The PeerChannelFactory 701 may not be directlyassociated with a PeerNode 705, but looks them up or creates them asrequired.

A PeerListenerFactory 703 object may be responsible for spawningPeerListeners 704. The PeerListenerFactory 703 manages the activelisteners and maintains a collection of active channels that thelisteners have spawned. A PeerListenerFactory 703 may be associated withexactly one PeerNode 705.

A PeerNode 705 may represent a node in a mesh and contains itsassociated configuration. The PeerNode 705 may be the owner of all theinternal components which implement the node. This class may alsocontain static methods for looking up existing nodes.

A Neighbor 711 may contain an underlying neighbor channel and tracks thestate of the channel. The Neighbor may expose methods for communicatingwith the neighbor node.

NeighborManager 710 may contain a collection of Neighbors 711. TheNeighborManager 710 may expose events which are aggregates of allNeighbors 711 (e.g. MessageAvailable). This object may provide theimplementation of a peer node service.

A Connector 708 object may handle sending and receiving connectionmessages (CONNECT, WELCOME, REFUSE, DISCONNECT).

A Maintainer 707 object may implement the mesh maintenance algorithms.The Maintainer 707 may contain the mesh signature, collection of knownmesh nodes, and collection of current mesh contacts.

A Flooder 709 may implement flooding logic. The Flooder may contain atable of recently seen messages.

A Synchronizer 706 may coordinate a light-weight contact/signaturesynchronization protocol over a neighbor channel.

Mesh Construction

A mesh may be identified by a name, or a mesh ID. A mesh ID is a validhostname (e.g., soccerpals) that may be resolved to an IP address,(e.g., 123.12.123.12). An address of a service on the mesh may bedesignated by a uniform resource identifier (“URI”) and is specifiedusing the peer channel schema prefix (net.p2p://), a mesh ID, a path,and a service name (e.g., net.p2p://soccerpals/path/service). AnEndpointAddress structure may be used to reference services in a meshand may consist, in part, of at least one URI.

FIG. 8, illustrates a process for creating a mesh using the object modelembodiment of the claims. (The following description will refer toobjects of the claimed system as described above using their aboveenumerated names, e.g., PeerNode, PeerChannel, etc.)

Generally, anytime a service or client desires to communicate with amesh, that service or client may be required to communicate through aPeerNode of the mesh Specifically, services may be associated with aPeerListenerFactory and clients may be associated with aPeerChannelFactory. This process may involve an application firstcreating 801 and opening 802 a PeerChannelFactory. ThePeerChannelFactory may be instantiated as an object within theapplication, and therefore, may be associated with the application. Nexta PeerChannel may be created 803 by calling a method on thePeerChannelFactory, which may be called CreateChannel. The PeerChannelmay then check to see if there is an associated PeerNode 804. If thereis an associated PeerNode, the PeerChannel may connect to that PeerNodeand open the PeerChannel 805, and begin receiving and sending messages806. Otherwise, if there is no existing PeerNode, the PeerChannel maycreate a new PeerNode 807, open the PeerChannel 808 (e.g., by calling anOPEN function on the PeerChannel and passing in an EndpointAddress), andopen the new PeerNode 809.

In opening a new PeerNode, the PeerNode may call a Resolver object whichis responsible for providing a name resolution service. There may benumerous Resolver methods including RegisterMeshID, UnregisterMeshID,etc. The Resolver method may implement a custom name resolution serviceor may use a Message Bus-provided resolution service such as Peer NameResolution Protocol (“PNRP”). The newly created PeerNode may call theResolver to register a node service 810, which is a service that isuniquely provided by each PeerNode for internal implementation purposes.This node service may be different from the application service thatinitiated the creation of the new PeerNode or that initiated theconnection to an existing PeerNode. By registering with the Resolver,other nodes may obtain a reference to the newly created PeerNode, viaits node service reference.

In addition to registering its node service, a PeerNode may query theResolver for other nodes in the mesh 811. Without calling the resolver'sResolveMeshId method, a node may not know if there are other nodes inthe mesh (unless one of the other nodes initiates a connection to thisnode). If there are no other nodes, the PeerNode may raise an indicationto the PeerChannel, which raises an alert to the Application. If thereare other nodes, the PeerNode may calls its Maintainer object to resolvethe mesh ID into a EndpointAddress of a remote node service. Once theEndpointAddress is obtained, the NeighborManager may be used to create aNeighborChannel to the NeighborNode 811. Once the NeighborChannel iscreated, a connection may be attempted by sending a CONNECT message 812.If a WELCOME message is received, the PeerNode may be opened and online,and a synchronization process begins. If the REFUSE message is received,the PeerNode may attempt additional connections. If the PeerNode doesnot find or connect to any other nodes, the PeerNode may set itself toan offline state 813, otherwise the PeerNode may be online 814, and mayreceive and send messages 815.

Generally, the process above may be similar for a PeerListener processexcept for the initial channel creation block. When dealing with aservice that is only interested in communicating with the mesh afterbeing solicited by a message targeted to that service, the service maycreate and open a PeerListenerFactory, instead of a PeerChannelFactory.The PeerChannel may then be used to create a PeerListenerFactory. Whenthe first message is received by a PeerNode matching the filtercriteria, the PeerListener may spawn a PeerChannel. Once the PeerChannelis created, two-way communications may be made similar the processdescribed above. A PeerListener, however, may also be configured with amessage filter such that it only notifies the application for messagesmatching the filter criteria.

When the application wants to flood a message, it may communicate with aPeerNode through its PeerChannel. The peer channel may notify theapplication whenever a message is available for it. Alternatively, ifthe implementation uses a PeerListener, the PeerListener may generate aPeerChannel and notify the application that a message has been receivedfor it. Once a PeerChannel is created, the application may receive andprocess it.

Each PeerNode may have a single associated NeighborManager. TheNeighborManager may be limited to a delivery and reception role and maybe tasked with maintaining a list of all its immediate neighbors, i.e.,PeerNodes directly connected to it, and for collecting messages directedto it and sending messages from the PeerChannels that belong to aPeerNode.

Neighbor Receives Connection Request

FIG. 9 illustrates the scenario of handling neighbor connections. When afirst node initiates a connection to a second node 901, theNeighborManager of the second node may be notified and may create aNeighbor object to track the remote first node 902. The NeighborManagermay notify its PeerNode 903, representing the second neighbor node,which in turn notifies the Connector. The first node's Connector startsa Connect protocol with the second node by sending a CONNECT message.The responding Connector may then send a response to the initiating nodeaccording to the following:

If the current number of neighbors is greater than or equal to a maximumvalue (described further in Mesh Maintenance section below), a REFUSEmessage may be sent back to the neighbor with a short list of neighborsand/or other known nodes 905 and the channel is closed 906. Otherwise aWELCOME message may be sent with a short list of neighbors and/or knownnodes 907.

If the channel has not been closed by the above process, the nodes mayexchange ADVERTISE messages that may contain the services advertised oneach node 908.

Synchronizing a Node

When a neighbor connects to another node on the mesh, the current stateof the mesh may be required to be synchronized to ensure that all nodesshare the same view of the mesh. This state includes a list of meshcontact nodes, along with a mesh signature (which is used for internalmesh maintenance functions, to be described below).

Peer Synchronizer may be a component of a PeerNode that is responsiblefor running the synchronization protocol between a pair of neighboringnodes. The synchronization process may involve the following steps whichare illustrated in FIG. 10. At block 1000, when a neighbor transitionsto Connected state, the initiating Synchronizer may start the syncprocess by sending a SyncRequest message. The SyncRequest message maycontain a list of abstracts of the contacts in the Maintainer's contactcache and the signature. Each contact abstract may contain the node IDof the contact node and the version number of the contact. For a newnode, this list may be empty.

At block 1005, upon receiving the SyncRequest message, the respondingSynchronizer may hand over the list of abstracts to a Maintainer. TheMaintainer may implement the mesh maintenance algorithms and may containthe mesh signature, collection of known mesh nodes and collection ofcurrent mesh contacts. At block 1010, the Maintainer, in turn, maycompare the abstract list with the contents of its contact cache. Atblock 1015, the Maintainer may build a list of contacts that are presentin its cache but missing from the abstract list (i.e., the initiatingnode does not have them) and adds the contacts that are newer than theones in the abstract list. At block 1020, an updated abstract iscreated. Any contacts that are missing from the responder's cache areadded or if the responder has an older version, the Maintainer may addthem into a new, updated abstract list. At block 1025, the contact list,the signature, and the new abstract list may be returned to theSynchronizer.

At block 1030, if the abstract list returned by the Maintainer isnon-empty, control may pass to block 1035 where the respondingSynchronizer sends its own SyncRequest message with this abstract listand the Signature. At block 1040, the Synchronizer may send a series ofSyncData messages with the contacts. The final contact chunk and thesignature may be are sent in the SyncEnd message. If at block 1030 theabstract list returned by the Maintainer is empty, the Sychronizer maynot send its own SyncRequest and control may pass to block 1040.

At block 1043, on the initiating side, a determination may be madewhether the initiating side sent a SyncRequest of its own. If theinitiator did not send a SyncRequest, the end of synchronization processmay be signaled at block 1045 when all the SyncData and the SyncEndmessages are sent. If the initiator did send its own SyncRequest, thesynchronization process may end when and when the SyncEnd message isreceived at block 1050.

At block 1055, on the responding side, a determination may be madewhether the responding side sent a SyncRequest of its own. If theresponder did not send a SyncRequest, the end of synchronization processmay be signaled at block 1060 when all the SyncData and the SyncEndmessages are sent. If the responder did send its own SyncRequest, thesynchronization process may end when and when the SyncEnd message isreceived at block 1065.

FIG. 11 may illustrate the exchange of various synchronization relatedmessages between a pair of neighbors, where the initiator is the newnode. FIG. 12 may illustrate the synchronization process between a pairof existing nodes in the mesh. FIG. 13 may illustrate thesynchronization process between an existing node and a new node, wherethe existing node is the initiator.

Sending/Flooding a Message

FIG. 14 illustrates the scenario of flooding a message. When theapplication wants to send a message 1401, it may call a send method ofthe PeerChannel method 1402, the PeerChannel may call the PeerNode 1403,which may call the Flooder to send the message 1404. The ID of the innermessage may be added to the Flooder's message table 1405, and theFlooder may encapsulate the inner message into an outer tunnelingmessage 1406 and send the message to all neighbors as a tunnelingmessage 1407. The outer tunneling message may be used only forcommunication on neighbor channels, without alteration to the innerapplication message. Tunneling may be done in order to maintain theintegrity of the inner message for handling and delivery only byinternal peer node components, while providing encapsulation headers anddelivery mechanisms for handling by the neighbor channels. This mayeffectively isolate transport mechanisms between the two pathways.

Receiving a Message

FIG. 15 illustrates the scenario of receiving a message. When a messageis received on a NeighborChannel associated with a PeerNode 1501, theNeighborManager may notify the PeerNode 1502, which may call its Flooder1503 to process the message according to its type.

For all flooded messages, the inner message may be extracted from theouter tunneling message 1504. The PeerNode may call the Flooder todetermine if the inner message has been seen before 1505. If it has, themessage may be closed and processing is complete 1506. If the innermessage has not completed propagating through the mesh (i.e., themessage should be flood further), further processing may occur.

If the inner message is an internal message for processing meshfunctions 1507, a PeerNode may forward the message to its correctinternal node object (e.g., Maintainer) 1508. These components processthe message as described further below. For signature messages, theMaintainer may determine that the message should stop flooding further1509, at which point the message is closed and processing may becomplete 1506. Otherwise, the inner message's ID may be added to theFlooder's message table 1516 and the inner message may bere-encapsulated by the Flooder into another outer tunneling message andsent to all neighbors except the neighbor from which the originalmessage was received 1517.

If the inner message is an application message 1510, the PeerNode maysearch for a channel object 1511 (e.g., a PeerChannel or a PeerListener)associated with the message's destination service. If a matchingPeerChannel is found, the message may be sent to the application/service1512 associated with the PeerChannel. Otherwise, if a matchingPeerListener is found, a new PeerChannel may be created to theapplication/service 1513 by calling AcceptChannel or BeginAcceptChanneland the message may be sent to the corresponding application.

the inner message is not an application message 1510 the inner message'sID may be added to the Flooder's message table 1516 and the innermessage may be re-encapsulated by the Flooder into another outertunneling message and sent to all neighbors except the neighbor fromwhich the original message was received 1517. Additional flood pruninglogic may be implemented in this process as well 1514, 1515. Forexample, some applications may implement a propagation filter interfaceobject 1514 (which may be called a IPeerMessagePropagationFilterinterface) associated with the Flooder to determine if a message shouldbe flooded further. If the Flooding filter interface determines thatthere should be no further flooding, processing is complete 1515.

Closing a Portion of the Mesh

The following are events that may occur in which a portion of the meshmay be disassembled, or closed.

Neighbor Initiated Disconnect: If a neighbor disconnects cleanly, theneighbor may send a DISCONNECT message. This message may be handled bythe Connector, which closes the neighbor channel. When the neighborchannel closes (either abruptly or via a formal disconnect process), theNeighborManager may notify the other internal node components. TheMaintainer may handle this event by performing a mesh maintenancealgorithm (described below). The PeerNode may handle this event bynotifying the application that the services advertised by the remotenode are no longer available. If this was the only neighbor connection,the node may now be offline.

PeerNode Initiated Disconnect: A neighbor may be disconnected locally(e.g., by the PeerNode) either because the peer node is closing orbecause the Maintainer chooses to prune the connection. When a neighboris closing, the local components may be notified. The Connector mayhandle this event by sending a DISCONNECT message to the neighbor. Oncethe Neighbor is closed, the application may be notified that the remotenode's advertised services are no longer available.

Closing a PeerChannel: When a channel is closed, it may be removed fromthe owning factory's channel collection and the reference to theassociated PeerNode is released.

Advertising a Service

One advantage of the claimed mesh system is that it may allow anapplication to use the mesh to locate services which the application canthen consume. In order to enable access to the services offered byvarious nodes on the mesh, applications may need to first retrieveinformation about its neighbors. In particular, an application may needto be able to enumerate services advertised on its neighbors.

To advertise a local service to neighbor nodes, the application may callan AddAdvertisedAddresses function of the PeerNode, specifying the localapplication service's EndpointAddress. This may cause the Maintainer toadd this service to its currently advertised list and send an ADVERTISEmessage to neighbors containing the updated advertised service list.Similarly, an application may un-advertise a service by calling aRemoveAdvertisedAddresses function of the PeerNode.

When the application advertises its service addresses, this informationis cached by the node and sent to neighbors. On receiving thisinformation, an event may be raised. This event may provide theapplication with the neighbor's node ID and all the EndpointAddresssadvertised on that node.

By advertising the addresses of an application's services, anapplication can open a channel directly to the neighbor's applicationservice, thereby enabling a private communication channel. To send amessage to a neighbor (rather than sending a message to the entiremesh), the application may be required to retrieve the list ofadvertised services on the neighboring node and decide which service tosend to. To find this list of services, the application may call afunction of the PeerNode to retrieve the advertised services, which maybe called GetNeighborAdvertisedAddresses, which collects the cachedservice information. The method returns a collection of EndpointAddresssto services advertised on the neighboring nodes along with theneighbors' node IDs.

The application may select one of these EndpointAddresss, and may use achannel of the underlying Message Bus (e.g., http, tcp, etc.—not aPeerChannel) to create a channel to the service. The application may usethis channel to directly communicate (off-mesh) with the neighbor'sservice.

Mesh Maintenance

FIG. 16 illustrates a mesh maintenance process in an embodiment of theclaims. Mesh connections may be determined by three parameters which maybe called cIdealNeighbors, cMaxNeighbors, cMinNeighbors. A node maymaintain a count of the number of neighbor nodes connected 1601. A nodemay attempt to maintain approximately cldealNeighbors connections toother nodes at any given time. A node may not establish a new outgoingconnection or accept a new incoming connection if it currently hascMaxNeighbors 1602, and will send a REFUSE message 1603 to any nodesattempting to connect to it. If the number of connections is belowcMinNeighbors at any time 1604, the node may attempt to establish moreconnections. The node may WELCOME pending channel requests 1605, 1606 ora node may use the list of known nodes that was communicated to it byits neighbors 1607 (via the WELCOME, REFUSE, and DISCONNECT messages).If this list is insufficient, it may attempt to resolve the mesh ID to anew node (e.g., by opening a new channel, as described above).

The values for cIdealNeighbors, cMaxNeighbors, and cMinNeighbors maydepend on a variety of factors including mesh size and mesh traffic.Because a cMinNeighbors value of one may cause a complete separation ifthe one and only connection is lost, a cMinNeighbors value of at leasttwo may be appropriate for any mesh. A high value of cMaxNeighbors maymean that a particular node is doing a very disproportionate amount offlooding on behalf of other nodes. A cldealNeighbors value betweencMinNeighbors nad cMaxNeighbors may be based on good redundancy, withminimum overhead.

Each node in the mesh may attempt to maintain the most useful set ofconnections as possible, where a connection's usefulness may bedetermined by the amount of unseen messages sent on it (in eitherdirection). Periodically, when a node has more than the cldealNeighbors1608, it may disconnect the least useful connection 1609.

Each node may have a node ID, which is a random 64-bit number. The meshhas a signature which may be computed as the lowest node ID present inthe mesh. The computation may be done by having the node with the lowestnode ID publish its ID as the signature. However, a node may notdirectly know that it has the lowest ID, so all nodes may attempt topublish their ID. A node may not publish if the mesh signature isalready lower than their ID. Also, each node may have a backoff periodbefore publishing which may be exponentially proportional to its nodeID, thereby helping to reduce the number of incorrect signaturepublications.

The mesh may have a set of contact nodes, which may be responsible forperiodically publishing the signature of the mesh as they see it.Whenever a node's view of the mesh signature becomes out of sync withthe view that the contacts publish 1610, the node may know that the meshhas been partitioned, and may attempt to reconnect 1611, after a randombackoff period, to one of the contacts that is out of sync. There is asmall chance that this procedure may not detect a partition. To mitigatethis, contact nodes may periodically attempt to resolve the mesh ID to anew (random) node and form a connection.

APIs

FIG. 17 may be an illustration a method in accordance with the claims.The method 1700 may be used in a peer networking enabled computeradapted to be part of a network of computing devices interoperating viaa peer networking protocol having an implementation of a peer networkingprotocol.

The success of a peer-to-peer protocol may depend on the protocol'sability to establish valid connections between selected entities.Likewise, the formation of groups in such a peer to peer network relieson this ability. However, one skilled in the art will recognize from thefollowing teachings that the methods of the present invention are notlimited to the particular peer-to-peer protocol.

The method 1700 may be embodied in an application programming interfacefor a software program that implements a set of device services. Themethods may be part of a peer listening factory that sets up a peerlistener and part of a peer channel factory that sets up a peer channelas explained previously. At block 1710, the method may serve requestsfor a maximum number of services to advertise to other computing deviceson the peer network. A default value may be 25, for example. Servicesmay be thought of as being computer programs or computer experiences fora user. Members of a group may not need to know about all the servicesavailable from every computing device in the group because excessiveadvertisement may clog up a network unnecessarily. The number ofservices to be advertised may be arbitrary or may be based on a formulasuch as in a smaller group with limited network traffic, more servicesmay be advertised while in a larger network with more network traffic,fewer services may be advertised. In addition, the number of servicesmay be advertised may be set. The number may be set by another member ofthe network or by an administrative member of the network. A samplecomputer code implementation may be as follows:

-   -   public int MaxAdvertisedAddressesPerNeighbor { get; set; }.

At block 1720, requests to determine if a message should be propagatedto additional computing devices on the peer network may be served. Thedetermination may also be though of as a filter on which messages shouldbe passed on to other computing devices on the network. The filter mayhave a limitless number of settings such as whether the message has beenreceived previously, whether the message has an intended recipient thatthe receiving computer recognizes, whether network traffic is high,whether the message is recent or old, etc. The default value may be nofilter meaning that all messages are forwarded. The filter may also beset. For example, if computer device known to the recipient goes offline and a message is received for that known computer device, then thefilter may be set to not forward the message. A sample computer codeimplementation may be as follows:

-   -   public IPeerMessagePropagationFilter MessagePropagationFilter {        get; set; }

At block 1730, requests for a port number used to contact a computingdevice on the peer network may be served. Ports may be used tocommunicate messages to the network and different computing devices onthe network may use different ports. Block 1740 may supply the port thecomputing device is using to send and/or receive messages to othermembers on the network. A default may be that the underlying transport(i.e., TCP, HTTP) selects the port. In addition, the port of computingdevice used to communicate with the network may be set. The port may beset by another member of the network or my an administrative member ofthe network. A sample computer code implementation may be as follows:

-   -   public Nullable<int>NeighborServicePort { get; set; }

At block 1740, request for a transport method used to contact computingdevice on the peer network may be served. A variety of transport methodsmay be available such HTTP or TCP. In addition, the transport method ofthe computing device to may be set. The transport method may be set byanother member of the network or by an administrative member of thenetwork. A sample computer code implementation may be as follows:

-   -   public Transport NeighborServiceTransport { get; set; }

At block 1750, requests regarding which resolver to use may be served.Because a particular user may connect to the network in various ways atvarious locations having different addresses, a unique identity may beassigned to the user or the group. This address may then need to beresolved such that the identity is tied to a particular address oraddresses through the protocol. One such peer-to-peer name resolutionprotocol is Peer Name Resolution Protocol (“PNRP”). For example, theresolver may convert a network address to a mesh id using PNRP. However,one skilled in the art will recognize from that the methods of thepresent invention are not limited to the particular peer-to-peerprotocol, but may be applied to other protocols with equal force. Inaddition, the resolver used by the computing device may be set. Theresolver may be set by another member of the network or by anadministrative member of the network. A sample computer codeimplementation may be as follows:

-   -   public IPeerResolver Resolver { get; set; }

From the above description, the method and system of the claims mayenable an application developer using a service oriented applicationframework to integrate multicast functionality with ease and convenienceusing the peer node objects. Using this framework, services havingmulticast functionality may be created without concern for TCP/IP orother underlying, lower-level communication protocols, because the peernode objects manage messaging using whatever protocol is available. Anadvantage of this system may be that meshes may be created that span theentire Internet, whereas multicast IP requires certain multicast IPenabled segments of the Internet (e.g., the “Mbone”) in order tooperate. The claimed system also provides an application based filteringmechanism in which the flow of messages may be intelligently controlledusing filter interfaces (e.g., message suppression may be useful inmaking the mesh more efficient and secure), which an IP multicastsolution does not provide.

Further, because the claimed system is built on top of a servicesoriented framework, application developers may not need to concernthemselves with programming from scratch a multicast solution, they onlyneed to worry about what multicast functionality they would like toimplement as part of their services. The peer node object model providesa base infrastructure so that developers can concentrate on developingmulticast enabled services. The described APIs also will makeprogramming easier.

Although the forgoing text sets forth a detailed description of numerousdifferent embodiments, it should be understood that the scope of thepatent is defined by the words of the claims set forth at the end ofthis patent. The detailed description is to be construed as exemplaryonly and does not describe every possible embodiment because describingevery possible embodiment would be impractical, if not impossible.Numerous alternative embodiments could be implemented, using eithercurrent technology or technology developed after the filing date of thispatent, which would still fall within the scope of the claims.

Thus, many modifications and variations may be made in the techniquesand structures described and illustrated herein without departing fromthe spirit and scope of the present claims. Accordingly, it should beunderstood that the methods and apparatus described herein areillustrative only and are not limiting upon the scope of the claims.

1. In a peer networking enabled computer adapted to be part of a networkof computing devices interoperating via a peer networking protocolhaving an implementation of a peer networking protocol, an applicationprogramming interface for a software program that implements a set ofdevice services comprising: serving requests for a maximum number ofservices to advertise to other computing devices on the peer network;serving request to determine if a message should be propagated toadditional computing devices on the peer network; serving requests for aport number associated with a port object used to contact a computingdevice on the peer network; serving requests for a transport method usedto contact the computing device on the peer network; and servingrequests regarding which resolver to use; wherein the port object isconfigured to receive a message from an application code, via a channelobject associated to the port object, to initiate the request for theport number.
 2. The application programming interface of claim 1,wherein the resolver converts mesh id to a network address using pnrp.3. The application programming interface of claim 1, further comprisingallowing the setting of the maximum number of services to advertise toother computing devices on the peer network.
 4. The applicationprogramming interface of claim 1, further comprising allowing thesetting of a filter to determine if a message should be propagated toadditional computing devices on the peer network.
 5. The applicationprogramming interface of claim 1, further comprising allowing thesetting of the port number used to contact a computing device on thepeer network.
 6. The application programming interface of claim 1,further comprising allowing the setting of the transport method used tocontact computing device on the peer network.
 7. The applicationprogramming interface of claim 1, further comprising allowing thesetting of the resolver to use.
 8. A computer readable medium havingcomputer executable instructions for use in a peer networking enabledcomputer adapted to be part of a network of computing devicesinteroperating via a peer networking protocol having an implementationof a peer networking protocol, providing an application programminginterface for a software program that implements a set of deviceservices comprising: computer executable instructions for servingrequests for a maximum number of services to advertise to othercomputing devices on the peer network; computer executable instructionsfor serving request to determine if a message should be propagated toadditional computing devices on the peer network; computer executableinstructions for serving requests for a port number associated with aport object used to contact a computing device on the peer network;computer executable instructions for serving requests for a transportmethod used to contact the computing device on the peer network; andcomputer executable instructions for serving requests regarding whichresolver to use; wherein the port object is configured to receive amessage from an application code, via a channel object associated to theport object, to initiate the request for the port number.
 9. Thecomputer readable medium of claim 8, wherein the resolver converts meshid to a network address using pnrp.
 10. The computer readable medium ofclaim 8, further comprising computer executable instructions forallowing the setting of the maximum number of services to advertise toother computing devices on the peer network.
 11. The computer readablemedium of claim 8, further comprising computer executable instructionsfor allowing the setting of a filter to determine if a message should bepropagated to additional computing devices on the peer network.
 12. Thecomputer readable medium of claim 8, further comprising computerexecutable instructions for allowing the setting of the port number usedto contact a computing device on the peer network.
 13. The computerreadable medium of claim 8, further comprising computer executableinstructions for allowing the setting of the transport method used tocontact computing device on the peer network.
 14. The computer readablemedium of claim 8, further comprising computer executable instructionsfor allowing the setting of the resolver to use.
 15. A computingapparatus, comprising: a display unit that is capable of generatingvideo images; an input device; a processing apparatus operativelycoupled to said display unit and said input device, said processingapparatus comprising a processor and a memory operatively coupled tosaid processor; a network interface connected to a network and to theprocessing apparatus; said processing apparatus being programmed to, ina peer networking enabled computer adapted to be part of a network ofcomputing devices interoperating via a peer networking protocol havingan implementation of a peer networking protocol, providing anapplication programming interface for a software program that implementsa set of device services comprising: serving requests for a maximumnumber of services to advertise to other computing devices on the peernetwork; serving request to determine if a message should be propagatedto additional computing devices on the peer network; serving requestsfor a port number associated with a port object used to contact acomputing device on the peer network; serving requests for a transportmethod used to contact the computing device on the peer network; andserving requests regarding which resolver to use wherein the resolverconverts mesh id to a network address using pnrp; wherein the portobject is configured to receive a message from an application code, viaa channel object associated to the port object, to initiate the requestfor the port number.
 16. The computing apparatus of claim 15, furthercomprising the processing apparatus being programmed to allow thesetting of the maximum number of services to advertise to othercomputing devices on the peer network.
 17. The computing apparatus ofclaim 15, further comprising processing apparatus being programmed toallow the setting of a filter to determine if a message should bepropagated to additional computing devices on the peer network.
 18. Thecomputing apparatus of claim 15, further comprising processing apparatusbeing programmed to allow the setting of the port number used to contacta computing device on the peer network.
 19. The computing apparatus ofclaim 15, further comprising processing apparatus being programmed toallow the setting of the transport method used to contact computingdevice on the peer network.
 20. The computing apparatus of claim 15,further comprising processing apparatus being programmed to allow thesetting of the resolver to use.